1. Technical Field
The present invention relates to an ultrasound diagnostic apparatus, and more particularly to an ultrasound diagnostic apparatus in which a modulated continuous wave is utilized.
2. Related Art
Continuous wave Doppler is a known ultrasound diagnostic apparatus technology in which a continuous wave is employed. In continuous wave Doppler technology, a transmission wave formed as a sinusoidal wave of several MHz is continuously radiated into a living organism, and a reflection wave from within the living organism is then continuously received. The reflection wave includes Doppler shift information generated by a moving element (e.g. blood flow) within the living organism. Accordingly, by extracting the Doppler shift information and applying frequency analysis thereto, a Doppler waveform which reflects information of velocity of the moving element, for example, can be formed.
Continuous wave Doppler technology in which a continuous wave is utilized is generally superior to Pulse Doppler, in which a pulse wave is utilized, for rapid acquisition of velocity measurements. Under such circumstances, the inventors of the present application have conducted research concerning continuous wave Doppler technology. In one of their achievements, the present inventors proposed the technology concerning Frequency Modulated Continuous Wave Doppler (FMCW Doppler) disclosed in JP 2005-253949 A.
However, use of a continuous wave makes continuous wave Doppler technology less suited for measuring a position. As such, typical continuous wave Doppler devices (i.e., devices in which the FMCW Doppler is not utilized) were unable to perform position measurement. In this regard, the present inventors proposed, in JP 2006-14916 A, a technology which enabled measurement of a position of a tissue within a living organism, in addition to measurement of the velocity of a tissue within the living organism, by using FMCW Doppler.
The FMCW Doppler technology described in the above-noted publications is a revolutionary technology providing a potential for new forms of ultrasound diagnosis. The present inventors have continued to research and improve this landmark technology.